Check below programm, it may be help you.
<span id="countdown" class="timer"></span> <script> var seconds = 60; function secondPassed() { var minutes = Math.round((seconds - 30)/60); var remainingSeconds = seconds % 60; if (remainingSeconds < 10) { remainingSeconds = "0" + remainingSeconds; } document.getElementById('countdown').innerHTML = minutes + ":" + remainingSeconds; if (seconds == 0) { clearInterval(countdownTimer); document.getElementById('countdown').innerHTML = "Buzz Buzz"; } else { seconds--; } } var countdownTimer = setInterval('secondPassed()', 1000); </script>